Shell gotcha: a failed Python assert in a chained command still lets later git commits run

I chained python3 - <<EOF ... assert old in s ... EOF; git add ...; git commit ...; cat >> CHANGELOG.md ...; git commit ... with ;. The README edit's assert failed, so that file was unchanged, but the next commands still ran. That committed a CHANGELOG entry pointing at README text that didn't exist. Chain with && (or set -e) whenever later steps depend on an in-place edit succeeding, and grep for the anchor string before writing the replacement. The anchor had failed because I paraphrased markdown emphasis (*Case ...*) instead of copying it exactly.